January 14, 2011

Transplant Treats Disease in the Eye

by ssavage

(Ivanhoe Newswire) -- A new eye transplant releases the medication dexamethasone within the eye to safely and effectively treat some types of uveitis, swelling and inflammation in the eye's middle layer, according to new research.

"Uveitis refers to a group of intraocular inflammatory diseases that cause 10 percent to 15 percent of blindness in the developed world," the authors were quoted as saying. "Despite advances in immunosuppressive treatments, corticosteroids remain the mainstay of therapy."

However, some patients can't tolerate or do not respond to systemic corticosteroids. To address this issue, an intravitreal (within the vitreous fluid of the eye), bioerodible and sustained-release implant was developed to deliver a glucocorticoid medication (dexamethasone) to the back of the eye. Careen Lowder, M.D., Ph.D., of the Cleveland Clinic Cole Eye Institute, and colleagues conducted a randomized controlled trial with 229 patients who had intermediate or posterior uveitis. Patients were either given an implant that administered 0.7 milligrams of the drug; one that administered 0.35 milligrams; or a sham procedure, which administered the dexamethasone but used a needleless applicator.

They found that after eight weeks, 47 percent of the 0.7-mg patients reported 0 vitreous haze, or hazy vision due to inflammation. Additionally, 36 percent of those who received the 0.35-mg implant reported 0 vitreous haze compared to 12 percent of the sham procedure patients.

In addition, the percentage of eyes that achieved at least a 15-letter improvement in visual acuity was two- to six-fold greater in both implant groups than in the control group throughout the study.

"Typically, the most common adverse events associated with intravitreal corticosteroids, which may have impacted use in the past, included increases in intraocular pressure [pressure within the eye] and cataract. On any given follow-up visit in the present study, substantial increases in intraocular pressure (to 25 millimeters of mercury or greater) occurred in less than 10 percent of treated eyes," the authors write. In addition, only one of 62 phakic (with lenses) eyes required surgery to remove a cataract.

"In conclusion, the present study demonstrated that in patients with non-infectious intermediate or posterior uveitis, a single dose of the dexamethasone intravitreal implant was well-tolerated and produced significant improvements in intraocular inflammation and visual acuity that persisted for six months," the authors conclude. "Overall, the 0.7-milligram dexamethasone intravitreal implant demonstrated greater efficacy than the 0.35-milligram dexamethasone intravitreal implant, with similar safety."